The present invention relates generally to an adjustable sliding-jaw wrench and, more particularly to an adjustable sliding-jaw wrench providing a ratcheting mode of operation.
An open-end wrench is a type of hand tool used to tighten or loosen a fastener, such as a nut or bolt. One type of open-end wrench is an adjustable sliding-jaw wrench, which uses a worm gear to drive a mating rack formed integrally with an adjustable sliding jaw. Rotating the worm gear adjusts the separation between the sliding jaw and a fixed jaw integrally formed with the handle of the wrench.
Adjustable sliding-jaw wrenches offer the particular advantage that the open-ended jaws can easily slip onto or off a fastener from the side. On the other hand, adjustable sliding-jaw wrenches cannot be used to rotate the fastener more than part of a single revolution unless the fastener is freely accessible. When rotation of the adjustable sliding-jaw wrench is hindered, the wrench must be removed and repositioned to further rotate the fastener.
Socket wrenches allow for a ratcheting mode of operation to torque a fastener without the need to remove and reposition the tool. Unfortunately, socket wrenches cannot slip onto or off of the fastener from the side and cannot be used when access to the top of the fastener is limited. Therefore, it is desirable to combine the features of an adjustable sliding-jaw wrench with a ratcheting mode of operation.
A number of solutions exist in the prior art for combining a ratcheting mode of operation with an adjustable sliding-jaw wrench. Many of the solutions require an extensive amount of manufacturing to accomplish. For example, some solutions use a camming operation or a pivoting handle to achieve the ratcheting effect. Although some of these wrenches may be effective, the difficulty and attendant cost of manufacturing makes them undesirable.
FIGS. 1A-C illustrate an example of a ratcheting adjustable wrench 10 in the prior art as disclosed in U.S. Pat. No. 5,746,099 to Janson. Referring to FIG. 1A, ratcheting adjustable wrench 10 is cast or stamped out of steel and then machined. Wrench 10 includes a wrench head 12 having a handle 14 extending therefrom. A fixed jaw 16 also extends from wrench head 12 opposite handle 14. A receiver 30 defines a longitudinal bore that extends through wrench head 12 and receives a movable member 40 therein. Movable member 40 includes a jaw 42 that opposes fixed jaw 16 and allows wrench 10 to clench a fastener F.
Movable member 40 also includes a toothed rack 44 that communicates with a large opening 50. Large opening 50 extends through wrench head 12 and accommodates a worm gear 70, a spindle 60 and a compression spring 62 therein. Spindle 60 is inserted into large opening 50 through a threaded aperture 64. Worm gear 70 and spring 62 are positioned in large opening 50. Worm gear 70 contains an axial bore (not shown), a widened portion of which receives one end of spring 62. Spindle 60 passes through spring 62 and worm gear 70 until the end of spindle 60 lands in an aperture 66 opposite threaded aperture 64. Spindle 60 then threads into threaded aperture 64 to support worm gear 70 and spring 62 within large opening 50. In this way, worm gear 70 rides on spindle 60, and spring 62 biases worm gear 70 to the top of large opening 50.
Large opening 50 extends slightly into receiver 30 so that worm gear 70 engages with rack 44 on movable member 40. A smaller opening 52 extends from large opening 50 on the side opposite from receiver 30. Smaller opening 52 accepts a locking member 80 that is slideably mounted within smaller opening 52. Locking member 80, shown partially cut-away in FIG. 1A, slides within smaller opening 52 and covers a compression spring 88 in smaller opening 52. Ideally, locking member 80 is assembled before the assembly of worm gear 70, spindle 60 and spring 62 as described above. Those skilled in the art will appreciate that wrench 10 offers a number of challenges to manufacture and assemble.
In FIG. 1A, locking member 80 engages worm gear 70 in a locked position. The biasing of spring 88 urges locking member 80 towards spindle 60 in order to support worm gear 70. In particular, a side protrusion 82 on locking member 80 is interposed between worm gear 70 and a sidewall 54 of large opening 50. With locking member 80 in this locked position, worm gear 70 cannot slide along spindle 60. Furthermore, movable member 40, which is engaged with worm gear 70, cannot move within receiver 30 unless worm gear 70 is rotated. With the support of locking member 80, movable jaw 42 remains stationary relative to fixed jaw 16 so that wrench 10 may tighten or loosen the fastener F.
In FIG. 1B, locking member 80 is retracted from worm gear 70 to an unlocked position within small opening 52. The retraction of locking member 80 overcomes the biasing of spring 88. With locking member 80 in the unlocked position, worm gear 70 is no longer blocked by protrusion 82 and may slide along spindle 60. Consequently, movable member 40, engaged with worm gear 70, may also slide within receiver 60. With this freedom of movement, movable jaw 42 may slide away from fixed jaw 16 and accommodate the wider corner-to-corner dimension of the fastener F.
Although the design allows adjustable jaw 42 to move in relation to fixed jaw 12 when in the unlocked position, some problems exist in the operation of the tool. One particular disadvantage in the tool lies in the engagement of locking member 80 with worm gear 70. As described in FIG. 1A, locking member 80 engages worm gear 70 when in the locked position. FIG. 1C illustrates a top view of the engagement of locking member 80 and worm gear 70.
With reference to FIG. 1A and more particularly to FIG. 1C, spindle 60 passes through a bore 72 of worm gear 70. Spring 62 surrounds spindle 60 and lies partially within bore 72 of worm gear 70. Locking member 80 is H-shaped with first and second protrusions 82a, 82b, a cross connector 84, and a slideway 86. Protrusions 82a, 82b interpose between worm gear 70 and sidewall 54 of large opening 50 to prevent worm gear 70 from sliding along spindle 60. Cross connector 84 may also interpose between worm gear 70 and sidewall 54. A portion of wrench head 12 is located within slideway 86, and spring 88 biases locking member 80 towards spindle 60 and worm gear 70.
Because worm gear 70 rides on spindle 60, the protrusions 82a, 82b and cross connector 84 cannot support worm gear 70 on its axial center 72. Protrusions 82a, 82b and cross connector 84 must fit around spindle 60 and spring 64 to accommodate them. Furthermore, the extension of the protrusions 82a, 82b under worm gear 70 is limited so that the protrusions 82a, 82b do not contact rack 44 of movable member 40. Therefore, locking member 80 only partially supports worm gear 70. The engagement of locking member 80 with worm gear 70 represents an inherently weak structure of the wrench 10.
When the locked wrench 10 in FIG. 1A is used to tighten or loosen the fastener F, the corners of the fastener F bear on movable jaw 42. Worm gear 70 is forced against locking member 80. Because the engagement between locking member 80 with worm gear 70 is not axially aligned with the force applied, moment forces may be created on the structure of worm gear 70, spindle 60 and locking member 80. With the forces not axially aligned, wrench 10 may fail when torquing the fastener F.
Furthermore, the structure of wrench 10 requires careful machining of each component of the worm gear 70, spindle 60 and locking member 80 to create the engagement of the locking mechanism. To avoid excessive xe2x80x9cplayxe2x80x9d between the components, stringent tolerances and tight interconnections are required. Tolerances that do not meet these requirements may also cause wrench 10 to wear or fail.
Besides posing inherent structural problems, the movement of locking member 80 poses additional operational difficulties. Although locking member 80 is supported on one side by sidewall 54 of large opening 50, locking member 80 lacks additional reinforcement when moving from the locked position in FIG. 1A to the unlocked position in FIG. 1B. Locking member 80 can thus dislodge when moving between the locked and unlocked positions.
When returning to a locked position from the unlocked position in FIG. 1B, locking member 80 must properly insert between the bottom of worm gear 70 and sidewall 54. Because locking member 80 includes the protrusions 82a, 82b, locking member 80 may catch the winding tooth or the side of worm gear 70 before spring 62 moves worm gear 70. Locking member 80 may also dislodge from smaller opening 52 if it catches on worm gear 70. Locking member 80, therefore, has a potential of jamming on the side of worm gear 70. This would particularly be the case when the user of wrench 10 in FIG. 1B releases locking member 80 before the jaws 16, 42 are fully ratcheted past the corners of the fastener F.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In view of the foregoing and other considerations, the present invention relates to an adjustable sliding-jaw wrench providing a ratcheting mode of operation.
In accordance with one aspect of the present invention, a wrench includes a wrench head having a fixed jaw thereon. A movable unit is disposed in the wrench head. The movable unit includes a rack partially extending into a first aperture in the wrench head and includes a jaw opposing the fixed jaw. The wrench also includes a worm gear positioned within the first aperture. The worm gear includes a rotatable portion and a spindle. The rotatable portion is engaged with the rack that is axially moveable within the first aperture between a first and a second position. The spindle extends axially from the rotatable portion and is axially moveable therewith. The spindle has a distal end and is slideably situated within a spindleway communicating with the first aperture. The wrench includes a locking mechanism positioned in a second aperture communicating with the spindleway. The locking mechanism is movable between a locked and an unlocked position. In the locked position, the locking mechanism is interposed between the distal end of the spindle and a side of the second aperture to maintain the worm gear in the first position.
In accordance with another aspect of the present invention, a wrench includes a wrench head having a fixed jaw. A first lamination defines one side of the wrench head. A second lamination defines another side of the wrench head. An intermediate lamination defines at least a portion of the wrench head and is situated between the first and second laminations. Each of the first, second and intermediate laminations defines a first aperture therein. A movable jaw unit, disposed in the wrench head, includes a jaw opposing the fixed jaw and a rack gear partially extending into the first aperture. A worm gear engages the rack gear and is movable within the first aperture between a first and a second position. The worm gear has a rotatable portion and a spindle extending axially from the rotatable portion. The spindle has a distal end that is slideably situated within a first cutaway communicating with the first aperture in the intermediate lamination. A locking mechanism is disposed in a second cutaway communicating with the first cutaway in the intermediate lamination. The locking mechanism is movable between a locked and an unlocked position. In the locked position, the locking mechanism is interposed between the distal end of the second spindle and a side of the second cutaway to hold the worm gear in the first position.
In accordance with still another aspect of the present invention, an adjustable jaw wrench includes a wrench head having a fixed jaw thereon. A movable unit disposed in the wrench head has a jaw opposing the fixed jaw. A worm gear is positioned in the wrench head and is engaged with the movable unit. The wrench includes means for moving the worm gear along an axial line of movement between a first and a second position. The wrench includes means for supporting the worm gear to retain the worm gear in the first position. The supporting means is aligned along the axial line of movement. The wrench also includes means for freeing the worm gear to move towards the second position.
In accordance with another aspect of the present invention, an apparatus for gripping a workpiece includes a first element having a fixed jaw thereon and a second element disposed in the first element. The second element has a rack thereon and a jaw opposing the fixed jaw. A rotatable portion is positioned in the first element to engage the rack, is movable along an axial line between a first and a second position and has an axial element extending therefrom. A blocking element positioned in the first element is movable between engaged and disengaged positions with respect to a distal end of the axial element. In the engaged position, the blocking element substantially aligns with the distal end of the axial element and maintains the rotatable portion in the first position. Moving the blocking element to the disengaged position frees the distal end of the axial element and allows the rotatable portion to move to the second position.
In yet another aspect, the present invention includes a method for selectively rotating a fastener with an adjustable jaw wrench or ratcheting a movable jaw and a fixed jaw of the wrench about the fastener. The method includes the following steps: interconnecting a worm gear with the movable jaw; providing the worm gear with a path of axial movement in the wrench head; allowing the wrench to rotate the fastener; and allowing the wrench to ratchet about the fastener. Allowing the wrench to rotate the fastener includes hindering the axial movement of the worm gear by selectively interposing a blocking element in the path of the axial movement of the worm gear. Allowing the wrench to ratchet about the fastener includes freeing the axial movement of the worm gear by selectively displacing the blocking element from the path of the axial movement of the worm gear.